Field of the Invention
The invention relates to a heat insulated wall having two surface layers disposed at a distance from one another and being at least substantially vacuum-tight in construction which together with an at least substantially vacuum-tight connection element enclose an evacuable space which is filled with an evacuable thermal insulation material.
With heat insulated walls based on vacuum insulation technology it is known for the outer surface layers, which are at a distance from one another, to be connected to one another in a vacuum-tight fashion by a connection profile which is substantially U-shaped in cross section. The connection profile is inserted between the surface layers in such a way that the free leg ends thereof face the edges of the surface layers and end substantially flush with them. With this type of connection of the two surface layers it is absolutely necessary to furnish the base of the connection profile with a thickness of material which must lie within the same order of magnitude as that of the surface layers. This is necessary in order to achieve some rigidity for the tensioning forces which are required as part of the manufacturing process and which have to be exerted exclusively outside the insulation compartment, owing to its lack of accessibility, on the heat insulated wall. As a consequence of the increased thickness of material in the area of the base of the connection profile, and when using inexpensive thermal insulation materials which serve as both supporting and insulating material and are to be introduced into the space between the surface layers, such as open-cell polyurethane foam or open-cell polystyrene foam or the like, a heat bridge is produced which has a considerable adverse effect on the insulation capacity of the heat insulated wall. To avoid this adverse effect, the known walls are filled with expensive fiber materials that in addition, owing to their relatively high specific weight, represent a marked increase in weight of the walls. Thereby, considerably hindering the handling of the walls in production or, where the latter are employed, for example, for a refrigeration device, such as a household refrigerator or home freezer, considerably hindering the mobility of the device.